Certain 1-pyridyl 2-mercapto-imidazole derivatives

ABSTRACT

The compounds are of the class of substituted 2mercaptoimidazole derivatives which have antiinflammatory utility. Illustrative examples are 1-(4-fluorophenyl)-5-methyl-2mercaptoimidazole and 1-methyl-5-phenyl-2-mercaptoimidazole.

United States Patent [72] Inventor Karl J. Doebel, Ossining, N.Y., and

Andre R. Gagneux, Basel, Switzerland [21] Appl. No 721,929 [22] Filed 1 Apr. 17, 1968 [45] Patented Nov. 23, 1971 [73] Assignee Geigy Chemical Corporation, Greenburgh,

N.Y. Continuation-impart of application Ser. No. 204,643, June 22, 1962, abandoned, which is a continuation-inpart of application Ser. No. 500,245,

21,1965, abandoned [54] CERTAIN l-PYRIDYL Z-MERCAPTO-IMIDAZOLE -7. E I I 4 Claims, No Drawing Figs.

V [52] US. Cl 260/2943 G 260/294.8 E, 260/294.8 l-l, 260/309 260/340.9, 260/326 N, 260/326 A, 260/552 R, 260/454, 260/592; 424/263 [51 Int. Cl C07d 31/50 [50] Field of Search 260/ 294.8 6

[56] References Cited Jones et al., Journal of the American Chemical Society, Vol. 71, December (1945). QB] A5.

Primary Examiner-Alan L. Rotman Attorneys-Karl F. Jorda, Bruce M. Collins & Martin J.

Spellman CERTAIN l-PYRIDYL Z-MERCAPTO-IMIDAZOLE DERIVATIVES Cross-Reference to Related Cases This application is a continuation-in-part of application,

Ser. No. 500,245, filed Oct. 21, 1965, now abandoned,

which is a continuation-in-part of application, Ser. No.

204,643, filed June 22, 1962. now abandoned.

Detailed Disclosure This invention relates to certain derivatives of Z-mercaptoimidazole which possess valuable pharmaceutical properties.

More specifically, the compounds of this invention are substituted Z-mercaptoimidazole derivatives which can be represented by the following structural formula:

l SR2 I wherein R is lower alkyl; lower alkenyl; cycloalkyl; cycloalkyl-lower-alkyl; monocarbocyclic aryl; monocarbocyclic aryl-lower-alkyl; di-lower-alkylamino-lower-alkyl; lower alkoxy-lower-alkyl: or pyridyl;

represents hydrogen, di-lower-alkylamino-loweralkyl. carbo-lower-alkoxy or lower alkylcarboxy, stands for hydrogen or lower alkyl, and

denotes lower alkyl or monocarbocyclic aryl, provided that R is lower alkyl only when R is monocarbocyclic aryl and that R. is pyridyl only when at least one of R R or R is a group other than hydrogen; and provided further that R, is lower alkyl only when R, is a group other than lower alkyl.

The term lower alkyl as used herein per se or as included in the term lower alkoxy means saturated monovalent aliphatic radicals of the formula -CmH2m+1 wherein m designates an integer of less than 5 and is inclusive of both straight chain and branched chain radicals except that the integer is less than 4 in carbo-lower-alkox'y, the term lower alkylene as used herein means unsaturated monovalent aliphatic radicals of the general formula C; Hz wherein n designates an integer of less than 5 and is inclusive of both straight chain and branched chain radicals and the term monocarbocyclic aryl as used herein means phenyl and phenyl mono-, dior tri-substituted by lower alkyl, lower alkoxy, halogen (fluorine, bromine, chlorine, iodine) or trifluoromethyl.

The compounds defined by the above formula can be synthesized, for example, by reacting a suitable primary amine, formaldehyde and an a-isonitrosoketone. The reaction mixture is then treated with a reagent which yields the hydrosulfide ion, metal sulfides, preferably sodium sulfide, potassium sulfide, calcium sulfide, etc.; ammonium sulfide and other equivalents. The compounds obtained may be further modified by hydrolysis and decarboxylation. Other modes of preparation of the compounds of this invention are illustrated in the examples given below.

The methods for the preparation of these compounds can be exemplified more fully by the following illustrative ex- 'amples. The temperatures therein are given in degrees centigrade.

EXAMPLE 1 1-(pMethoxyphenyl)-5 -methyl-2-mercaptoimidazole a. 1- (p- Methoxyphenyl) 2 mercapto 4 carbethoxy 5 methylimidazole A 37 percent aqueous formaldehyde solution (10.0 ml.) and 12.32 g. of p-anisidine were mixed in 30 ml. of ethanol. After three minutes a heavy precipitate had formed. Ethyl isonitrosoacetoacetate (15.9 g.) were then added, the mixture heated to reflux and a brisk stream of hydrogen sulfide was bubbled through for one hour. The reaction was then stopped and cooled to 5. Recrystallization of the resulting precipitate from ethanol and then from chloroform/pentane afiorded 13.0 g. (45 percent) of material; m.p. 203-205. 1 Anal. for C l-l N O S Calcd: C 57.50, H 5.52. N 9.59.8 10.97 Found: C 57.72. H 5.52, N 9.80. S 11.22 U.V. (Methanol) A, max: 223 mp; c 14000; A, max: 271 3 5 2 31115; QLl-BJQH l- 20 Inn-I b. 1 -(p M ethoxyphenyl)-2-mercapto-4-carboxy-S-methylimidazole l-(p-Methoxyphenyl)-2-mercapto-4-carbethoxy-5-methylimidazole (27.8 g.) was refluxed with 500 ml. of 3N sodium hydroxide for 1 hour; then cooled, filtered and the filtrate acidified and the precipitated acid collected on a Buchner funnel. Recrystallized from dioxane. the desired compound was obtained in a yield of 97 percent; m.p. 265 (dec.) Anal. for CHHIZNZOQS (MW 264.23)

Calcd:C 54.54, H 4.58. N 10.60, S 12.12

Found: C 54 6 7 I;1 4.78, N 10.37. S 11.79 7 UN. (Methanol) A. max: 223 mu: 5 14000: A: max: 271 mu; e 14400.

2 Mercapto- 1-(pmethoxyphenyl) -4 carboxy- 5 methylimidazole (10.7 g., 40 mM) was heated under nitrogen to 280 with magnetic stirring. After 5 minutes the CO2- evolution subsided, heating was continued for another 5 minutes and 50 ml. of ethanol was carefully added once the residue had solidified. Recrystallization of the reddish mixture from hot ethanol gave 6.2 g. (65 percent) of the desired compound, m.p. 224227.

Anal. for C H ON S (M.\V. 220.22

Calcd: C 59.99, H 5.49, N 12.72, S 14.54

Found: C 59.77, H 5.58. N 12.54,S 14.54

Ultraviolet spectrum:

)tMax. MeOH 2230 A (e= 24.000 2670 A (e= 15,000

HCl 2230A(e=2l,000

2670 A (e= 14,000) NaOH 2230 A 22,000)

EXAMPLE 2 1-(4-Methoxypheny1)-2-methylmercapto-5-methylimidazole H ydrochloride I-(4-Methoxyphenyl)-2-mercapto-5methylimidazole (4.4 g., 0.02 mole) was suspended in water (20 ml.) and 3N NaOH (6.6 ml.); the mixture was heated to 100 and dimethyl sulfate (0.04 mole, 5.66 ml.) was added. Sufiicient dilute NaOH solution was added to maintain reaction mixture just basic to bromcresol purple indicator while heating at 100' for /2 hour. The reaction mixture was cooled, neutralized to pH 8-9 with saturated sodium carbonate solution and extracted with chloroform (5 X 100 ml.). The chloroform extract was washed with water. dried over sodium sulfate and evaporated to dryness. The resulting oil (4.4 g.)

instead of water.

' Anal. for Q H SCIN OS (M.WTZWOJ?) Calcd: C 53.22, H 5.58, N 10.35, S 11.84, Cl13.09 Found: C 53.00, H 5.48, N10.39, S 11.90, Cl13.36

Ultraviolet spectrum: t 1:2 225 mp, 255 mp EXAMPLE 3 1 ,5-Dimethyl-2-rnercaptoimidazole 15 This compound was prepared according to the procedure in Burtles et a1., .1. Chem. Soc., 127, 581 (1925). The compound was recrystallized fromethanol (charcoal treatment) Anal. for C5H8N2S (M.W. 128.2)

Calcd: C 46.84, H 6.29, N 21.85, S 25.05

Found: C 46.86, H 6.85, N 21.80, S 24.76

1-(n-Butyl)-5-methyl-2-mercaptoimidazole a. N-(n-Butyl)-N -[1-(2-hydroxypropyl)] thiourea A solution of butyl isothiocyanate (5.75 g., 0.05 mole) in dry benzene (12 ml.) was added dropwise to a solution 3 of l-amino-2-propanol (3.75 g., 0.05 mole) in anhydrous benzene (12 ml.) while cooling in ice bath. The mixture was stirred at room' temperature overnight. Product (9.25 g., m.p. 8890) crystallized. Two recrystallizations from ethyl acetate ml.) yielded screening sample (8.1 g., m.p. 8991).

Aiiij'fbr CsHisFESO (M.W. 196.31)

Calcd: C 50.491181 9.53, N 14.72

Found: Cv 50.19, N 9.59, N 14.77 I Ultraviolet spectrum: 212 my. (6, 12,200);

. 242 mp. (e, 13,600)

b. Desired Compound A mixture of N-butyl-N'-[1-(2-hydroxypropyl)]-thiourea (9.5 g., 0.05 mole), anhydrous toluene (250 ml.) and anhydrous cyclohexanone (150 ml.) was heated under anhydrous conditions to 100. Aluminum isopropoxide M on M15;

(20.4 g., 0.1 mole) was added with the aid of toluene ml.)

and the reaction mixture was heated at 125 with stirring for 2 hours. The reaction mixture was cooled in an ice bath; water (25 ml.) and sulfuric acid (10 percent. 50 ml.) were added carefully. The reaction mixture was again heated under reflux for I: hour. cooled to room temperature. Additional water (300 ml.) was added. The toluene layer was separated and the aqueous mixture was extracted with chloroform (3 X 500 ml.). The combined toluene-chloroform extract was washed with water, dried over sodium sulfate and evaporated to dryness, first under vacuum and then under high vacuum at 100. Crystallization of the residue from ethyl acetate (20 ml.) gave desired product (5.9 g., m.p. v 142145). Recrystallization from isopropanol (15 ml.) yielded screening sample (5.4 g., m.p. 142144). The identical product can be obtained by interaction of l-amino 2,2-ethylenedioxypropane with butyl isothiocyanate,.follo wed by acid treatment. Anal.,for.C H ,N S (M.W. 170.28)

Ca1c d-:,.C 56.42, H 8.29. N 16.45. S 18.83

Foundz C 56.38, H 8.21.N 16.28. S 18.82

EXAMPLE 5 1.5-Dimethyl-Z-(methylmercaptohmidazole hydrochloride A solution of 1.5-dimethyl-2-mercaptoimidazole (10.2 g., 0.08 mole) and methyl iodide 22.7 g., 0.24 mole. 9.9 ml.)

in anhydrous methanol (200 ml;) ivas heated under reflux for two hours. The solution was evaporated to dryness. The residue was suspended in water ml.) and the pH was adjusted to 9-10 with saturated sodium carbonate solution. The aqueous mixture was extracted with chloroform (4 X 200 ml.), the chloroform extract was washed with water, dried over sodium sulfate and evaporated to dryness to give oil (1 1 g.). To a solution of the oil in isopropanol was added 9N ethanolic HCl (12 m1.) while cooling. The resulting solution was evaporated to dryness and the residue crystallized from isopropanol-isopropyl ether (3: 1 20 ml.) to give desired compound (12.3 g., m.p. 142144). Recrystallization from isopropanol-isopropyl ether (2:1, 30 ml.) yielded screening sample (1 1.3 g., m.p.141143). Anal. for C H CIN S (M.W. 178.70)

Calcd: C 40.32, H 6.20, N 15.68, 8 17.94, Cl 19.84

Found: C 40.14, H 6.29, N 15.42, S 17.87, Cl19.86

EXA M PLE 6 1-(4-F1uorophenyl)-5-methyI-Z-mercaptoimidazole a. N-Acetonylphthalimide N-Acetonylphthalimide was prepared by a slight modification of the method of R. E. Lancaster and C. A. Vanderwert, J. Org. Chem. 23. 1208 (1958). A mixture of potassium phthalimide (500 g.). l-chloropropanone (345 ml.) and anhydrous benzene (750 ml.) was stirred under reflux for 5 hours and then at room temperature overnight. This 0 suspension was filtered, the salts were well washed with benzene and the benzene solution was evaporated to dryness. Recrystallization of the crude product from isopropanol ml.) gave desired compound (295 g., m.p. 121123).

b. 1-Phtha1imido-2,2-ethylenedioxypropane A solution of N-acetonylphthalimide g., 0.84 mole). ethylene glycol (78 g., 1.26 mole) and p-toluenesulfonic acid (4 g.) in anhydrous benzene (1250 ml.) was heated under reflux with continuous water separation for 8 hours. Recrystallization of the residue from ethyl acetate (ca. 75 ml.) gave desired product g., m.p. 8691) which was satisfactory for use in the next reaction. Recrystallization of 5 g. from cyclohexane (30 ml.) gave analytical sample (4.0 3., mp. 9093 0. l-Amino-2,Z-ethylenedioxypropane 1 Phthalimido 2.2 ethylenedioxypropane (134.4 g., 0.525 mole), hydrazine hydrate (0.785 mole. 30.1 ml.) and water (875 ml.) were heated under reflux for 2 hours. The solution was cooled, sodium hydroxide (3N. 150 ml.) was added and the mixture was continuously extracted with methylene chloride overnight. The methylene chloride solution was dried over sodium sulfate. evaporated to dryness and the residue was distilled under reduced pressure to give desired compound (34.5 g., b.p. 5656.5/10 mm. N11 1.4426). Redistillation of small fraction gave analytical sample (b.p. 5757.5/10 mrn. N 1.4423).

d. N-(4-Fluorophenyl) N'-[1-(2.2-ethylenedioxy) propyl] thiourea 4-Fluorophenyl isothiocyanate (4.59 g., 0.03 mole) was dissolved in ethanol (24 ml.); 1-amino-2,Z-ethylenedioxypropane was added while cooling and crystallization occurred immediately. The mixture was heated under reflux for onehalf hour, cooled, and the crystalline product (7.2 g., m.p. 125-127) was collected. Recrystallization from isopropanol (30 ml.) gave screening sample (6.5 g., m.p. 125127). Anal. for C12H|5N202SF (M.W. 270.33)

Calc'd: C 53.31, H 5.59, N 10.36. 5 11.86

Found: C 53.40, H 5.72, N 10.22, S 11.90

Ultraviolet spectrum m 245 mu(s. 14.000) I cooled, and the product (5.3 g., m.p. 268273 dec.) was collected. Recrystallization from methanolethanol (2:1,-

150 m1, reduce volume to 75 ml.) gave screening sample (4.5 g., m.p. 2658 dec.). Ultraviolet spectrum 3 270 m (6. 10,000)

Anal. for c.0H. N.s 1 \/1.w.20s.2s)

Calcd: c, 57.66, 11,4.35, N, 13.45, s, 15.40 5 1 37.61, H, 4.38, N, 13.26, s, 15.33

EXAMPLE 7 l-Allyl-5-methyI-Z-mercaptoimidazole 1-Amino-2,2-ethylenedioxypropane (7.02 g., 0.06 mole) was added to a cooled solution of allyl isothiocyanate (5.94 g., 0.06 mole) in isopropanol (48 ml.). The mixture was heated under reflux for one-half hour, then cooled. Hydrochloric acid (conc., 4.8 ml.) was added, and the mixture was again heated under reflux for one hour. Product (4.6 g., m.p. 133-l35) crystallized on cooling. Recrystallization from isopropanol (25 ml.) gave screening sample (3.8 g., m.p. 132135). Anal. for C1H N S (M.W. 154.24)

Calcd: C 54.50, H 6.54, N 18.16, 5 20.79 Found: C 54.49, H 6.84, N 18.19,S 20.86 Ultraviolet spectrum: g lt (a, 15,000)

EXAMPLE 8 1-Butyl-5-methyl-2-(carboethoxymercapto)-imidazole .hydrochloride Ethyl chloroforrnate (2.17 g., 0.02 mole) was added to a cooled suspension of 1-butyl-5-methyl-2-mercaptoimidazole (1.7 g., 0.01 mole) in anhydrous benzene (10 ml.).,

The mixture was stirred at room temperature for 2 hours. and solid product was collected (2.7 g., m.p. 110 dec.). Recrystallization of 3.9 g. of product from ethyl acetateisopropanol (10.1 g., 30 m1.) gave screening sample (2.1 g., m.p. 106 dec.). Recrystallization can also be achieved from isopropanolethyl ether. Anal. for C H MO SCI (M.W. 278.81)

Calcd: C 47.38, H 6.87, N 10.05, 8 11.50, Cl 12.72 Found: C47.01, H 6.96,N 10.19, S 11.59. Cl12.52

Ultraviolet spectrum: Mm 250 my. (6, 10,000)

EXAMPLE9 l-Ethyl5-methyl-2-mercaptoimidazole Ethyl isothiocyanate (4.35 g., 0.05 mole) is dissolved in isopropanol (reagent grade, 40 ml.). l-Amino-2,2-ethylenedioxypropane (5.85 g., 0.05 mole) was added and the mixture was heated under reflux for ,6 hour. Hydrochloric acid (conc., 4.0 ml.) was added and the solution was again heated under reflux for 1 hour. Product (5.5 g., m.p. 1869-188) crystallized on cooling. Recrystallization of 6.4 g. of desired compound from isopropanol (30 ml.) gave screening sample (5.4 g., m.p. 185-187).

Thin layer chromatography-solvent: CHCl 95; 3A ethanol, 5; detector: phosphomolybdic acid. Anal. fDl' csHmNgs Calcd: C 50.66, H 7.9, N 19.70

Found: C 50.43, H 6.95, N 19.48

EXAMPLE l0 1-(4-Fluorophenyl)-5-methyl-2- (dimethylaminoethylmercapto)imidazole mercaptoimidazole (6.24 g., 0.03 mole) in anhydrous methanol (40 ml.) After addition was complete, the mixture was heated under reflux for 2 hours. The mixture was cooled and insoluble material (1.8 g., m.p. 350) was removed by filtration. The mother liquor was evaporated to dryness; the residue (10 g.) was suspended in water (10 ml), the pH was adjusted to 9 with saturated sodium carbonate solution and the mixture was extracted with chloroform. The resulting semisolid (7 g.) was suspended in isopropanol (20 ml.); solid (starting material, 1.0 g.) was filtered off. The mother liquor was evaporated to dryness and the residue was distilled under reduced pressure; first fraction,-0.6 g., b. p. 131/0.08, no; 1.5611; second fraction, 4.4 g., b.p. 131- 135/0.08, no 1.5617. The two fractions were recombined, dissolved in isopropanol (reagent grade, 10 ml.) and ethanolic hydrochloric acid (9.5 N, 11 ml.) was added. The solution was evaporated to dryness and the residue was crystallized from isopropanol (15 ml.) to give salt (6.0 g., m.p. 173- 177 dec., hygroscopic). The salt was redissolved in water (10 ml), the solution was adjusted to pH 9 with saturated sodium carbonate solution and extracted with chloroform (4 X 50 ml.). The chloroform solution was dried over sodium sulfate, evaporated to dryness and the residue was distilled under reduced pressure to yield screening sample (2.85 g., m.p. l2ll26/0.05 mm..n,fi 1.5608). AnalTt'or'C HmN SF"('M.W. "279.37) w Calcd: c 60.19, H 6.49, N 15.04.811.48

Found: c 60.16, H 6.58, N 14.91 s 1 1 .1o Ultraviolet spectrum: ag g 259 mp.

EXAMPLE 11 1-Butyl-5-methyl-2-(dimethylaminoethylmercapto)imidazole A solution of 1-buty1-5-methyl-Z-mercaptoimidazole (6.8 g., 0.04 mole) and dimethylaminoethyl chloride (6.5 g., 0.06 mole) in anhydrous methanol (60 ml.) was heated under reflux with stirring for 2 hours. The mixture was cooled and insoluble material (1.5 g., m.p. 300) was removed by liltration. The mother liquor was evaporated to dryness and the residue was distilled under reduced pressure to yield oil (5.4 g., b.p. 108112/3.07 mm. m, 1.5185). While cooling. ethanolic hydrochloric acid (9.5 N, 6 ml.) was added and the resulting solution was evaporated to dryness. Slow crystallization occurred from isopropanol, isopropyl ether (1:1, 20 ml.); yield 5.2 g., m.p. 116120 dec., hygroscopic. Above salt (6 g.) was dissolved in water 10 ml.) pH was adjusted to 9 with saturated sodium carbonate solution and solution was extracted with chloroform. The resulting oil was distilled under high vacuum to yield screening sample (2.6 g., b.p. 104105/0.05 mm., m, 1.5168). Anal. fOrC H N S (M.W. v

Calcd: C 59.70, H 9.60, N 17.41 S 13.28

Found: C 59.85, H 9.86, N 17.20, S 13.18 Ultraviolet spectrum: 32 224 mg, 253 my.

EXAMPLE l2 1-(4-Fluorophenyl)-2-mercaptoimidazole p-Fluorophenyl isothiocyanate (12.24 g., 0.08 mole) was added to a cooled solution of aminoacetaldehyde diethyl acetal (10.64 g., 0.08 mole) in isopropanol (64 ml.). The mixture was heated under reflux for A hour. The mixture was cooled, conc. hydrochloric acid (6.4 ml.) was added and the mixture was again heated under reflux for 2 additional hours. Crystallization occurred on cooling. yield, 9.0 g., m.p. 205207. A total of 9.8 g. of crude product was treated with charcoal in methanol (200- ml.). The methanol solution was re-evaporated to dryness and the residue was twice recrystallized from ethanol (75 ml.) to give screening sample (6.9 g., mp. 205 207). Anal. for C H N SF (M.W. 194.23)

Calcd: C 55.65. H 3.63. N 14.42.S 16.51

Found: C-55.98. H 3.76.N 14.20,S 16.62 Ultraviolet spectrum: 1 2" 276 mp.(e,8,600)

" Ultraviolet spectrum: me

7 EXAMPLE 13 l-Methyl-S phenyl-2-mercaptoimidazole w-Aminoacetophenone hydrochloride (10.32 g., 0.06 mole) was added to a cooled solution of methyl isothiocyanate (4.38 g., 0.06 mole) in isopropanol (reagent grade, 60 ml.); sodium bicarbonate (5.04 g., 0.06 mole) was then added. The mixture was first stirred at room temperature for 1 hour and was then heated under reflux for 3 hours. Isopropanol was removed under reduced pressure and the residue was dissolved in a mixture of water (25 ml.) and chloroform (50 ml.). The chloroform layer was separated and the aqueous solution was further extracted with chlorofrom (3X50 ml.). The combined chloroform extract was washed with water, dried over sodium sulfate and evaporated to dryness. The colored residue (6.0 g.) was dissolved in methanol (200 ml.); the solution was twice treated with charcoal and reevaporated to dryness. The residue was recrystallized from isopropanol (50 ml.) three times to give screening sample (4.5 g., m.p. 178180). Anal. for C H N S (M.W. 190.27)

Calcd: C 63.12, H 5.30,N 14.73, S 16.85 Found: C 63.35, H 5.47, N 14.60, S 16.87 Ultraviolet spectrum: gain 269 m;1.(e, 15,400)

EXAMPLE 14 1-Cyclohexyl-5-methyl-2-mercaptoimidazole Cyclohexyl isothiocyanate (8.46 g., 0.06 mole) was added to a cooled solution of 1-amino-2,Z-ethylenedioxypro- .pane (7.02 g., 0.06 mole) in isopropanol (reagent grade,

48 ml.). The mixture was heated under reflux for /2 hour, cooled and conc. hydrochloric acid (4.8 ml.) was added. Heating under reflux was continued for 1 hour. Product (8.2 g., m.p. 204206) crystallized on cooling. Recrystallization from isopropanol (50 ml.) yielded screening sample (7.3 g, mp. 205 207).

Thin layer chromatography: 95 CHCl 3A Ethanol. Anal. for C ,5H1 N (M1W. 196.32)

Calcd: C 61.18,H 8.22, N 14.27, S 16.33

Ultraviolet spectrum: 515 265 my. (6, 14,300)

EXXMFLE 15 1-(3-Fluorophenyl)-5 -methyl-2-mercaptoimidazole 3-F1uorophenyl isothiocyanate (6.12 g., 0.04 mole)- was added to a cooled solution of 1-amino-2,2-ethylenedioxypropane (4.68 g., 0.04 mole) in isopropanol (reagent grade, 32 ml.). The mixture was heated under reflux for 56 hour; this was cooled, conc. hydrochloric acid (3.2 ml.) was added and heating under reflux was continued for an additional hour. Product (7.8 g., m.p. 229231) crystallized on cooling. Recrystallization from methanol (reagent grade, 100 ml.) gave screening sample (6.7 g., m.p. 227-229).

' Anal. for CIoHQNQS F (M.W. 208.26)

Calcd: C 57.66, H 4.35, N 13.45, S 15.40 Found: C 57.60, H 4.43, N 13.23, S 15.12

262 my. (e, 10,600)

EX A M PLE l 6 1-(4- Fluoropheny1)-5 -phenyl-2-mercaptoimidazole p-Fluorophenyl isothiocyanate (7.65 g., 0.05 mole) was dissolved in isopropanol (reagent grade, 50 ml.). The solution was cooled, w-aminoacetophenone hydrochloride (8.6 g., 0.05 mole) and sodium acetate (anhydrous, 4.1 g., 0.05 mole) were added. The mixture was heated under reflux for 5 hours. lsopropanol was removed by distillation under reduced Ultraviolet spectrum: W

EXAMPLE 17 1-(4-Fluorophenyl)-5-methyl-2- imidazolemercaptoacetic acid 1-(4-Fluorophenyl)-5-methyl-2-mercaptoimidazole (7.3 g., 0.035 mole) was suspended in 5 percent aqueous sodium hydroxide solution. Chloroacetic acid (3.85 g., 0.0385 mole) was added and the mixture was stirred at room temperature overnight (18 hours). The resulting solution was acidified to pH 1-2 with conc. hydrochloric acid and extracted with chloroform (7X200 ml.). The crude product (7.5 g.) was recrystallized three times from benezene (150 ml.) to give screening sample (5.0 g., m.p. l64166). Thin layer chromatography 50 Acetic acid, 50 water.

for

Calcd: C 54.12, H 4.17, N 10.52

Found: C 53.86, H 4.07, N 10.52

Ultraviolet spectrum: my 262 my (6. 5100) EXAMPLE l8 1-C yclopropylmethyl-5-methyl-2-mercaptoimidazole a. Cyclopropylmethyl isothiocyanate A solution of aminomethylcyclopropane hydrochloride (19.4 g., 0.18 mole) in water (50 ml.) was added dropwise to a mixture of thiophosgene (20.7 g., 0.18 mole), calcium carbonate (50 g.), water (50 ml.) and chloroform (75 ml.)

. maintained at 0 and agitated with vibromixer. After addition was complete, the reaction mixture was agitated at 35- 40 for 3 hours. The reaction mixture was filtered to remove salts, the chloroform layer was removed and aqueous layer was extracted with chloroform (3 X 200 ml.). The combined chloroform extract was washed first with 5 percent hydrochloric acid and then water, dried over sodium sulfate and evaporated to small volume. Product (15.8 g., b.p. 707 1l8 mm.) was distilled. Anal.

Calc'd: N 12.37, S 28.33

Found: N 12.43, S 28.53

b. Desired Compound A mixture of cycl opr opylmethyl isothiocyanate (9.04 g., 0.08 mole), 1-amino-2,2-ethylenedioxypropane (9.36 g., 0.08 mole) in isopropanol (56 ml.) was heated under reflux for hour. The reaction mixture was cooled, hydrochloric acid (conc. 5.6 ml.) was added and the mixture was again heated under reflux for /2 hour. Crystallization occurred on cooling; yield: 6.4 g., m.p. 153l55. This was dissolved in methanol, the methanolic solution was treated with charcoal and evaporated to dryness. Two recrystallizations from ethyl acetate ml.) gave screening sample (4.7 g., m.p. 174176). On drying at 60 and 0.1 mm. Hg melting point changes to 154 1 56. Anal. for cgH zNzs Calcd: C 57.10, H 7.19, N 16.65, S 19.05

Found: C 56.91, H 7.11,N 16.3],S 19.07

EXAMPLE 19 1-(3-Trifluoromethylphenyl)-5-meth yl- Z-mercaptoimidazole a. 3-Trifluoromethylphenyl isothiocyanate A solution of m-aminobenzotrifluoride (34.9 g., 0.22 mole) 292 ml1.(e. 14,000) I in chloroform (50 ml.) was added dropwise to a mixture of thiophosgene (25.0 g., 0.217 mole), calcium carbonate (30 g.), water (70 ml.) and chloroform (70 m1.) maintained below 10 in an ice-salt bath and agitated by means of a vibromixer. After addition was complete, the mixture was agitated at 35-40 for 3 hours. The reaction was then cooled, the salts were filtered off, the chloroform layer was separated and the aqueous portion was further extracted with chloroform (3 X200 ml.). The combined chloroform extract was washed first with 5 percent hydrochloric acid, then with water, dried over sodium sulfate and evaporated to small volume. Product (30.6 g., b.p. 8892) 8 mm. was distilled. Anal.

Calcd: N6.89,S 15.78

Found: N 6.98,S 16.27

b. Desired Compound 7 I V A mixture of 3-trifluoromethylphenyl isothiocyanate (12.18 g., 0.06 mole), 1-amino-2,2-ethylenedioxypropane (7.02 g., 0.06 mole) and isopropanol (48 ml.) was heated under reflux for 92 hour. Hydrochloric acid (conc., 4.8 ml.) was added and the mixture was again heated under reflux for 1 hour. Product (10.6 g., m.p. 197199) crystallized. Two recrystallizations from isopropanol (75 ml.) yielded screening sample (7.8 g., m.p. 196-198). Anal. for C H9N F S (M.W. 258.28)

Calcd: C 51.15, H 3.52,N 10.85, S [2.41

Found: C 51.22, H 3.56, N 10.70, S 12.27 Ultraviolet spectrum: ga 257 my. (6, 10,500)

EXAMPLE 20 1-(3-Trifluoromethylphenyl)-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal (7.98 g., 0.06 mole) in 25 ml. of isopropanol was added slowly to a cooled solution of 3-trifluoromethylphenyl isothiocyanate (12.18 g., 0.06 mole) in isopropanol (25 ml.). The reaction mixture was then heated under reflux for /2 hour and cooled. Hydrochloric acid (conc., 4.8 ml.) was added and heating under reflux was continued for 2 hours. Product (4.7 g., m.p. 155156) crystallized on cooling; second crop: 2.8 g., m.p. 155 157. Recrystallization from isopropanol (20 ml., charcoal) gave screening sample (4.2 g., m.p. 155158).

Thin layer chromatography: 95 CHCl;;, 5 3A EtOH Anal. for C10H7F3N2S Calcd: C 49.18, H 2.89,N 11.47,S 13.13

Found: C4944, H 3.04,N 11.42, S 13.43

Ultraviolet spectrum: g? 245 mp.(e,9,300); 279 my.

EXAM P LE 2 1 1-(B-phenethy1)-5-methyl-Z-mercaptoimidazole A solution of B-phenethyl isothiocyanate (8.15 g., 0.05 mole) in isopropanol (20 ml.) was cooled in a three-neck flask. 1-Amino-2,Z-ethylenedioxypropane (5.85 g., 0.05 mole) and additional isopropanol (20 ml.) was added. The reaction mixture was stirred under reflux for /2 hour, and cooled. Hydrochloric acid (conc., 4 ml.) was added and heating under reflux was continued for 1 hour. Product (8.2 g., m.p. 151-154) crystallized on cooling. Recrystallization from ethyl acetate (50 ml.) gave yellow product (7.3 g., m.p.154156); a methanol solution (200 ml.) was treated with charcoal and reevaporated to dryness. Two further recrystallizations from ethyl acetate yielded product (6.1 g., m.p. 153155). One further recrystallization from isopropanol ml.) gave screening sample (4.35 g., m.p. 152154.

Thin layer chromatography: 95 CHCl 5 3A EtOH Anal. forC H N S (M.W. 218.31)

Found: C 66.22. H 6.39, N 13.00, S 14.67 Ultraviolet spectrum: n gn 2 4 300 EXAMPLE 22 1-n-Propyl-5-methyl-Z-mercaptoimidazole Propyl isothiocynate (8.08 g., 0.08 mole) was added to a cooled solution of 1-amino-2,Z-ethylenedioxypropane (9.36 g., 0.08 mole) in isopropanol (64 ml.). The mixture was heated under reflux for /2 hour; this was cooled, hydrochloric acid (conc., 6.4 ml.) was added, and heating under reflux was continued for an additional /2 hour. Product (7.6 g., m.p. 160165) crystallized on cooling. Recrystallization from ethyl acetate (75 ml.) gave yellow crystals (6.3 g., m.p. 162165). A methanolic solution of the above was treated with charcoal and reevaporated to dryness. One further recrystallization from ethyl acetate and two recrystallizations from isopropanol (15 ml.) gave screening sample (3.3 g., m.p. 162l64).

Thin layer chromatography: CHCli, 5 3A EtOH. Anal. for C1HuN S (M.W. 15 6.26)

Calcd: c 53.81, H 7.74, N 17.92. 3 20.53

Found: C 5404, H 7.87, N 17.63, S 20.53 Ultraviolet spectrum: my 265 m l-(e. 15,600)

EXAM PLE 23 1-Phenyl-Z-mercaptoimidazole Phenyl isothiocyanate (14.85 g., 0.11 mole) was added to a cooled solution of aminoacetaldehyde diethyl acetal (14.63, 0.11 mole) in isopropanol (88 ml.). The mixture was heated under reflux with stirring for 92 hour. Hydrochloric acid (conc., 8.8 ml.) was added, and heating under reflux was continued for 3 hours. Product (9.7 g., m.p. 177-179) crystallized on cooling. A methanol solution ml.) was treated with charcoal and reevaporated to dryness. Two recrystallizations from isopropanol (50 ml.) gave screening sample (6.8 g., m.p. 178180).

Thin layer chromatography: 95 CHCL, 5 3A Ethanol Anal. for CyHttNzS (M.W. 176.24)

Calcd: C 61.33, H 4.58,N 15.90,S 18.19

Found: C 61.34. H 4.75. N 15.90.S 17.97 Ultraviolet spectrum: 1-1 219 mu (6. 11.000).

279 mp(e,7.500)

EXAMPLE 24 l-(B-Diethylaminoethyl)-5-methyl-Z- mercaptoimidazole Hydrochloride a. Diethylaminoethyl isothiocyanate A solution of diethylaminoethylamine (25.17 g.. 0.217 mole) in chloroform (50 ml.) was added dropwise to a mixture of thiophosgene (25.0 g.. 0.217 mole). calcium carbonate (30.0 g.), water (70 ml.) and chloroform (70 ml.) maintained at less than 10 in an ice bath and agitated thoroughly with vibromixer. After the addition was complete. the reaction mixture was agitated at 3540 for 3 hours. The reaction mixture was filtered to remove salts. the chloroform layer was removed, the aqueous layer was rendered alkaline to pH 9 with saturated sodium carbonate solution and extracted with chloroform (3X200 ml.). The chloroform extracts were combined, washed with water. dried over sodium sulfate and evaporated to a small volume under low vacuum. Product (12.1 g., b.p. 102103/8 mm.. m, 1.5039) was distilled.

b. Desired Compound A solution of 1-amino-2,Z-ethylenedioxypropane (5.85 g., 0.05 mole) in isopropanol (20 ml.) was added to a cooled solution of diethylaminoethyl isothiocyanate (7.90 g., 0.05 mole) in 20 ml. isopropanol. The reaction mixture was heated under reflux for /2 hour. The reaction mixture was again cooled in an ice bath. ethanolic hydrochloric acid (9.9N. 10 ml.) was added and the reaction mixture stirred under reflux for 1 hour. Product (8.8 g.. m.p. l84l86) Anal. for C H aoClN S 249.80)

Calcd: C 48.07, H 8.07, N 16.82, Cl 14.19. S 12.84

Found: C 47.90, H 8.21,N 16.62. Cl 14.09, S 12.91 Ultraviolet spectrum: my; 26 my. (e, 13,900)

EXAMPLE 1-(4-Fluorophenyl)-4,5-dimethyl-2-mercaptoimidazole a. 3-Phthalimido-2-butanone A mixture of potassium phthalimide (105.7 g., 0.57 mole).

'3-bromo-2butanone (90.6 g., 0.6 mole) and anhydrous benzene (90 ml.) was stirred under reflux for 5 hours. The reaction mixture was filtered hot and the salts were thoroughly washed with boiling benzene. The benzene solution was evaporated to dryness, and the residue was recrystallized from isopropanol ml.) to yield desired product (75.6 g., m.p. 8183). Recrystallization from isopropanol gave analytical sample'(m.p. 8284). Cf. Gabriel, B. 46, 1346. Anal. forC l-1 NO 7 Calcd: C 66.35, H 5.10, N 6.45

Found: C 66.47, H 5.1 2 ,N 6.54 Ultraviolet spectrum: Am? 295 my, 249 mp, 220 mp.

N.M.R. spectrum conforms with assigned structure.

b. 3-Phthalimido-2,2-ethylenedioxy butane I A solution of 3-phthalimido-2-butanone (54.3 g., 0.25 mole), ethylene glycol (24.8 g., 0.40 mole) and p-toluene sulfonic acid (1.3 g.) in anhydrous benzene (400 ml.) was heated under reflux with continuous water separation for 4 hours. The solution was cooled, was washed first with saturated sodium bicarbonate solution (75 ml.), then with water, dried over sodiul sulfate and evaporated to dryness. The residual oil was distilled under high vacuum to yield oil (61.0 g., b.p. 126128/0.033 mm. Hg rm 1.5485) which solidifies on cooling. Redistillation gave analytical sample (b.p. 146 147/0.1 mm. Hg, a 1.5510, m. p.59-62). Anal. for C14H15NO4 Calcd: C 64.63, H 5.74, N 5.22

Found: C 64.36. H 5.79, N 5.36

c. 3,3-Ethylenedioxy 2-butylamine A mixture of 3-phthalimido-2,Z-ethylenedioxybutane (51.0 g., 0.195 mole) and 25 percent KOH solution (200 mls.) was heated under reflux with stirring for 2% days. The alkaline solution was extracted with methylene chloride (4X200 ml.). The methylene chloride extract was dried over sodium sulfate and distilled under water vacuum. Product (12.85 g., b.p. 606l/l 1 mm. Hg, n 1.4431) distilled. Anal. for CeHwNOz Calcd: C 54.94, H 9.99, N 10.68

Found: C 54.84, H 10.19, N 10.71

d. Desired Compound 7 p-Fluorophenyl isothiocyanate (7.65 g., 0.05 mole) was added to a cold solution of 3,3-ethylenedioxy-2-butylamine (6.55 g., 0.05 mole) in isopropanol ml.). The reaction mixture was heated under reflux with stirring for E6 hour. The reaction mixture was cooled in an ice bath. Hydrochloric acid (conc., 4.0 ml.) was added and the reaction mixture was heated under reflux with stirring for 3 hours. Product (9.6 g., m.p. 259-61) crystallized on cooling. Two re- 65 crystallizations from ethanol (100 ml.) yielded screening sample (6.1 g., m.p. 260- 3).

Ultraviolet spectrum: 1:2 275p. (e, 10,700)

Thin layer chromatography: 90 CHCh, 10 3A ethanolshows presence of faint impurity. Anal. for CnHuFNzS I Calcd: C 59.44, H 4.99, N 12.60, S 14.42

Found: C 59.12. H 4.98. N 12.51. S 14.62

EXAMPLE 26 1-(2-Pyridyl)-5 -methyl-2-mercaptoimidazole a. Pyridine-Z-isothiocyanate scribed by A. E. S. Fairfield and D. A. Peak,J. Chem. Soc. 1955, 796.

si ed QQmP End 1-Aniino-2,2-ethylenedioxy propane (7.02 g., 0.06 mole) in isopropanol (24 ml.) was added slowly to a cooled solution of pyridine-Z-isothiocyanate (8.16 g.) in isopropanol (24 ml.). The mixture was heated under reflux for A hour and cooled in an ice bath. Ethanolic Hydrochloric acid (12 ml., 9.9 N) was added and the reaction mixture was stirred under reflux for 1 hour. Product (9.8 g:, m.p. 206-8) crystallized. The product (the hydrochloride salt) was suspended in water (30 ml.), the pH was adjusted to 9 with saturated sodium carbonate solution and the suspension was extracted with chloroform (3X60 ml.). The chloroform extract was washed with water, dried over sodium sulfate and evaporated to dryness to give solid (7.8 g., m.p. 185-7). The free base was treated with charcoal in methanol solution ml.), the methanolic solution was reevaporated to dryness, and the product was twice recrystallized from isopropanol (60 ml.) to yield screening sample (4.4 g., m.p. -7). Ultraviolet spectrum: MR2 255 my. (5, 11,700)

Thin layer chromatography: 90 CHCh, 10 3A EtOH Anal. fOl' C9H9N3S Calcd: C 56.51, H 4.75, N 21.96, S 16.77

Found: C 56.28, H 4.81, N 21.69, S 16.88

EXAMPLE 27 1-Benzyl-5-methyl-Z-mercaptoimidazole A solution of benzyl isothiocyanate (17.9 g., 0.12 mole) in isopropanol (40 ml.) was added to a cooled solution of 1-amino-2,2-ethylenedioxypropane (0-12 mole, 14.04 g.) in isopropanol (45 ml.). The reaction mixture was stirred under reflux for 1 hour and then cooled. Hydrochloric acid (conc., 9.5 ml.) was added, and the mixture was again stirred under reflux for 5 hours. Product (5.25 g., m.p. 230-4) crystallized on cooling. Recrystallization, first from isopropanol (300 ml.) and subsequently from methanol (200 ml.) yielded screening sample (3.8 g., m.p. 235 8).

Ultraviolet spectrum: Ami? 267 my. (6, 14,000)

Thin layer chromatography: 90 CHCb, 10 3A ethanol. Anal. for C||H|2N2S (M.W. V v d W Caic'd: C 64.66, H 5.92, N 13.71. S 15.70

Found: C 64.54, H 6.07, N 13.43, 5 15.72

EXAM P LE 28 1-(4-Chlorophenyl)-2-mercaptoimidazole a. Aminoacetaldehyde diethylacetal isothiocyanate A solution of aminoacetaldehyde 'diethylaccml (27.0 g.. 0.2 mole) in chloroform (50 ml.) was added dropwise to a mixture of thiophosge ne (25 g., 0.217 mole), calcium carbonate (30.0 g.), water (70 ml.). and chloroform (20 .ml.), maintained at less than 10 by means of an ice-salt bath and agitated thoroughly with vibromixer. After the addition was complete the reaction mixture was agitated at 35-40 for 3 hours. The reaction mixture was filtered to remove salts. the chloroform layer was removed. the aqueous layer was rendered alkaline to pH 8-9 with saturated sodium carbonate solution and extracted with chloroform (3X200 ml.). The chloroform extracts were combined, washed with water. dried over sodium sulfate and evaporated to small volume under low vacuum. Product (30.7 g., b.p. l0ll03/10 mm.) was distilled. (Cf. Easson. A.P.T.. and Pyman, F. L.,.1. Chem. Soc. 1932. 1806).

b. Desired Compound A solution of aminoacetaldehyde diethylacetal isothiocyanate (10.0 g., 0.0575 mole) in isopropanol (25 ml.) was added dropwise to an ice-cooled solution of p-chloroaniline (7.36 g.. 0.0575 mole) in isopropanol (25 ml.). The mixture was then heated under reflux for /fi hour and cooled. Hydrochloric acid (conc. 48 ml.) was added and heating under reflux was resumed for 3 hours. Product (8.7 g.. m.p. 222224) crystallized on cooling, was dissolved in hot methanol: the methanolic solution was treated with charcoal and reevaporated to dryness. Two recrystallizations of the residue from isopropanol (150 ml.) gave screening sample (5.33 g., m.p. 222224).

Thin layer chromatography: 90 CHCIB. 10 3A EtOH Anal. for C HTCIN S (M.W. 210.69) c6160; c 51.31.11 3.34. N 13.30, 1322.0 16.83"

Found: C 51.51, H 3.28. N 13.31.515.23, Cl 16.94 Ultraviolet spectrum: a? 222 mp1 (5. 21,000);

EXAM P LE 29 l-(3,4-Dichlorophenyl)-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (10.0 g.. 0.0575 mole) in isopropanol, 25 ml.) was added dropwise to an ice-cooled solution of 3,4-dichloroaniline (9.3 g.. 0.0575 mole) in isopropanol (25 ml.). The mixture was then heated under reflux for V2 hour and cooled. Hydrochloric acid (conc.. 4.8 ml.) was added and heating under reflux was resumed for 3 hours. Product (12.9 g., m.p. 241- 243 dec.) crystallized. This was recrystallized from methanol (charcoal. 400 ml.) to yield white product (7.1 g., m.p. 24l244). Further recrystallization from ethanol (ca. 150 ml.) gave screening sample (6.2 g., m.p. 239242 dec.).

Thin layer chromatography: 90 CHCl 3A EtOH Anal. for CgHgClgNgs (M.W. 245.13)

Calcd: C 44.10, H 2.47. N 11.43, 5 13.08, Cl 28.93

Found: C 44.37. H 2.49. N 11.70. S 13.23, Cl 29.19 Ultraviolet spectrum Ail/L22" 226 ma (6. 19.000);

EXAMPLE 30 1-(4-Methoxypheny1)-2-mercaptoimidazole A solution of aminoacetaldehyde diethyl acetal isothiocyanate (10.0 g., 0.0575 mole) in isopropanol (25 ml.) was added dropwise to an ice-cooled solution of p-anisidine (7.12 g., 0.0575 mole) in isopropanol (25 ml.). The mixture was then heated under reflux for hour and cooled. Hydrochloric acid (conc. 4.8 ml.) was added and heating under reflux was continued for 3 additional hours. Product (5.7 g., m.p. 214216) crystallized. Two recrystallizations from ethanol (150 ml.) gave screening sample (4.45 g.. m.p. 215218 dec.).

Thin layer chromatography: 90 CHCl 10 3A EtOH Anal. for C OH N SO (M.W. 206.27)

Calcd: C 58.22, H 4.89, N 13.58, S 15.55

Found: C 58.47, H 4.98, N 1388, 815.55

Ultraviolet spectr m! M352 230 mp. (e, 13,500);

EXAMPLE 31 1-(3- Pyridyl)-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (14.0 g., 0.08 mole) in isopropanol (30 ml.) was slowly added to a cooled solution of 3-aminopyridine (7.52 g., 0.08 mole) in isopropanol (35 ml.). The reaction mixture was heated under reflux for )6 hour and cooled in an ice bath. Ethanolic hydrochloric acid (9.9 N, 16 ml.) was added. Heating under reflux was resumed for 3 hours. The product (14.8 g., m.p. 271273) crystallized as the hydrochloride salt. This was dissolved in water (ca 1111.), the solution was neutralized to pH 8 with saturated sodium carbonate solution yielding a tan precipitate (l 1.3 g., m.p. 247250 dec.).

This was recrystallized from methanol (charcoal, 250 ml.) to

give product (9.2 g., m.p. 249-251 dec.). Two additional recrystallizations from methanol (200 ml.) gave screening sample (7.5 g., m.p. 248250 dec.).

Thin layer chromatography: CHCl 10 3A EtOH Anal. for CgH7N3S (M.W. 177.23)

Calcd: C 54.21. H 3.98, N 23.71, S 18.09

Found: c 34.31. N 23.33, s 18.05

Ultraviolet spectrum: M1122 248 mp. (e, 11,300); shoulder at 300 mp.

EXAMPLE 32 1-(2.3-Dimethylphenyl)-2-mercaptoimidazole yielded screening sample (6.8 g., m.p. 265-- 268 dec.).

Thin layer chromatrography: 90 CHCl 10 3A EtOH Anal. for CHHHNZS (M.W. 204.30)

Calcd: c 64.68, H 5.52, N 13.70, 5 13.70

Found; C 64.47 1l 6.00, b11353, S 15.85 Ultraviolet spectrum: A)? 264 ma (6. 12.700)

EXAMPLE 33 1-(2,4-Difluorophenyl)-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (12.25 g.. 0.07 mole) in isopropanol (30 ml.) was added slowly to an ice cooled solution of 2.4-difluoroaniline (9.03 g.. 0.07 mole) in isopropanol (30 ml.). The mixture was then heated under reflux for /2 hour and cooled. Hydrochloric acid (cone. 5.6 ml.) was added and heating under reflux was continued for 3 hours. Product (11.2 g.. m.p. 209212) crystallized on cooling. Two recrystallizations from ethanol ml.) gave screening sample (4.1 g., m.p. 212-214); low recovery due to accidental loss.

Thin layer chromatography: 90 CHC1 10 3A EtOH Anal. for C H N SF (M.W. 212.23) 7 V Found: C 51.03. H 308,14 13.47. S 15.32

Ultraviolet spectrum: x1152" 227 mp. (e, 12,000);

268 ma (e. 11.000)

EXA MPLE 34 1-(4-Trifluoromethylphenyl )-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (12.25 g.. 0.07 mole) in isopropanol (30 ml.) was added slowly to an ice cooled solution of p-aminobenzotrifluoride (11.27 g., 0.07 mole) in isopropanol (35 ml.). The mixture was then heated under reflux for 6 hour and cooled. Hydrochloric acid (conc. 4.8 ml.) was added. and heating under reflux was continued for 3 additional hours. Product (8.98 g.. m.p. l94197) crystallized on cooling. Recrystallization first from isopropyl ether (charcoal. 600 ml.) and then from benzene (100 ml.) yielded screening sample (5.7 g., m.p. l96l98).

Thin layer chromatography: 90 CHCl- 10 3A EtOH Anal. for C H F;.N S (M.W. 244.25)

Anal. C QH1FN2S (M.W. 194.24)

Calc'd: C 49.17, H 2.89, N 11.47, S 13.13 Found: C 49.42, H 3.03, N 11.29, S 13.39

Ultraviolet spectrum: 811 221 245 my. (6, 11,100):

EXAMPLE 35 1-(3-F1uorophenyl)-2-mercaptoimidazole A solution of aminoacetaldehyde diethyl acetal (10.64 g., 0.08 mole) in isopropanol (30 ml.) was slowly added to an ice-cooled solution of 3-fluorophenyl isothiocyanate (12.24 g., 0.08 mole) in isopropanol (30 ml.); the mixture was then heated under reflux for /2 hour and cooled. Hydrochloric acid (conc., 6.4 ml.) was added and heating under reflux was resumed for 1 hour. Product (9.4 g., 158-160) crystallized on cooling. Two recrystallizations from isopropanol (ca.

m1.) gave screening sample (7.5 g., m.p. 159-162).

Thin layer chromatography: 95 CHCl 5 3A EtOH Calcd: C 55.65, H 3.63, N 14.43, S 16.51

Found: C 55.75, H 3.62, N 14.22, S 16.80 Ultraviolet spectrum: x1132 289 mp. (e, 6.200)

EXAMPLE 36 1-(2,6-Dimethylphenyl)-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (14.0 g., 0.08 mole) in isopropanol ml.) was added slowly to an ice-cooled solution of 2,6-dimethylaniline (9.68 g., 0.08 mole) in isopropanol ml.). The mixture was then heated under reflux for b hour and cooled. Hydrochloric acid (conc., 6.5 ml.) was added and heating under reflux was 1 continued for 8 hours. Product (1 1.3 g., m.p. 308 dec.) crystallized. Two recrystallizations from ethanol (400 ml.) yielded screening sample (7.8 g., m.p. 301306 dec.).

Thin layer chromatography: 90 CHCl 10 3A EtOH Anal. for cnH zNgs Calcd: C 64.68, H 5.92, N 13.70. S 15.70 Found: C 64.60, H 5.95, N 13.82, S 15.51 Ultraviolet spectrum: x12 2 263 mu (6, 13,800)

' EXAMPLE 37 l-(2-Fluorophenyl)-2-mercaptoimidazole recrystallization from isopropanol (75 ml.) yielded screening sample (8.5 g.. m.p. 187190).

Thin layer chromatography: 90 CHCl 10 3A EtOH Cal cd: c 55.65, H 3.64.18 14.42 5 65 a t sl? 9. H LN. 1-L.; -Z Ultraviolet spectrum: 260 my. (a, 9,300)

EXAMPLE 38 1-(2-Chloro-5-trif1uoromethylphenyl)-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (14.0 g.. 0.08 mole) in isopropanol (30 ml.) was added slowly to a solution of 2-ch10ro-5-trifluoromethylaniline (15.68 g.. 0.08 mole) in isopropanol (35 ml.) precooled in an ice bath. The mixture was then heated under reflux for hour and cooled. Hydrochloric acid (conc.. 6.4 ml.) was added, and heating under reflux was continued for 8 hours. Product (13.5 g.. m.p. 202 205) crystallized. Recrystallization first from benzene (ca. 500 ml.) and then from ethyl acetate (150 ml.) yielded screening sample (8.1 g., m.p. 204-- 206).

Thin layer chromatography: CHClg, 10 3A EtOH Anal. for CmHgClFgNzS Calcd: C 43.09. H 2.18, N 10.05, 5 11.50, Cl 12.72 Found: C 43.28, H 2. 1 0. N 10.22, S 11.82, C1 12.62 Ultraviolet spectrum: m2" 259 mu (6, 12,600)

EXAMPLE 39 1-(2,6-Dichloropheny1)-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (10.50 g.. 0.06 mole) in isopropanol (30 ml.) was slowly added to an ice-cooled solution of 2.6-dichloroaniline (9.60 g., 0.06 mole) in isopropanol (25 ml.). The mixture was then heated under reflux for V2 hour and cooled. Hydrochloric acid (conc., 4.8 ml.) was added, and heating under reflux was continued for 18 hours. Product (12.8 g., m.p. 300-305 dec.) crystallized. Two recrystallizations from methanol (400 ml.) yielded screening sample (8.4 g., m.p. 302305 dec.).

Thin layer chromatography: 90 CHCl3. 10 3A EtOH Anal. for C9H5ClzNzS (M.W. 245.14) MW M Calcdz C 44.10. 112717181 1'1.43,s 13.07, Cl 28.93

Found; C 44.03. H 2.45. N 11.72. 5 13.13. Cl 28.84 Ultraviolet spectrum: x5 3 263 mp. (e, 13.800)

EXAMPLE 40 1-(4-Bromophenyl) Z-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (12.25 g., 0.07 mole) in isopropanol (30 ml.) was added slowly to an ice-cooled solution of p-bromoaniline (12.0 g., 0.07 mole) in isopropanol (30 ml.). The reaction mixture was heated under reflux for A hour and cooled. Hydrochloric acid (conc.. 5.6 ml.) was added and heating under reflux was continued for 3 hours. Product (14.86 g.. m.p. 244249 dec.) crystallized. Two recrystallizations from ethanol (charcoal, 1.000 ml.) yielded screening sample (1 1.2 g.. m.p. 244248).

Thin layer chromatography: 90 CHClg. 10 3A EtOH Anal. for C H BrN S (M.W. 255.16)

Calcd: C 42.35. H 2.77. N 10.99. S 12.53. Br 31.31

Found: C 42.65. H 2.80. N 11.22. S 12.52, Br 31.32 Ultraviolet spectrum: x1312" 290 ma (6. 6.400)

EXA M PLE 41 1-(4-Fluoro-Z-methylphenyl)-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (10.50 g.. 0.06 mole) in isopropanol (25 ml.) was added to an ice-cooled solution of 4-fluoro-2-methylani1ine (7.5 g., 0.06 mole) in isopropanol (25 ml.). The resulting solution was heated under reflux for V2 hour. and cooled. Hydrochloric acid (conc.. 5 ml.) was added and the mixture was heated under reflux for 8 additional hours. Product (7.6 g.. m.p. 211-215) crystallized on cooling. Two recrystallizations from isopropanol (200 ml.. charcoal) yielded screening sample (5.4 g.. m.p. 2l6-218).

Thin layer chromatography: 90 CHCl, 10 3A EtOH Anal. for CwHnFNzS Calcd: C 57.67. H 4.36. N 13.45, S 15.40

Found: C 57.82. H 4.42. N 13.73. S 15.46

EXAMPLE 42 1 -(4-lodophenyl )-2-mercaptoimidazole A solution of aminoacetaldehyde diethylacetal isothiocyanate (8.75 g.. 0.05 mole) in isopropanol (20 ml.) was added to an ice-cooled suspension of p-iodoaniline (10.95 g., 0.05 mole) in isopropanol (20 ml.). The resulting reaction mixture was heated under reflux for b hour and cooled. Hydrochloric acid (conc., 4.0 ml.) was added and heating under reflux was continued for 3 hours. Product (11.2 g., m.p. 245248 dec.) crystallized. Three recrystallizations from ethanol (250 ml., charcoal) yielded screening sample (7.20 g., m.p. 249- 251 dec.).

Thin layer chromatography: 90 CHCI 10 3A EtOH Anal. for C H IN S (M.W. 302.15)

Calcd: C 35.77, H 2.33, N 10.28 Eoun d: c 35.97, H 2.32, N 10.07 Ultraviolet spectrum: 11422 237 mp. (e, 26,600);

EXAMPLE 43 1-(4-F luorophenyl)-4-methyl-2-ethylmercaptoimidazole hydrochloride a. a-Aminopropionaldehyde diethylacetal a-Aminopropionaldehyde diethylacetal was prepared from abromopropionacetal as described by R. Burtles et al.. J. Chem. Soc. 1925, 581.

b. Desired Compound I A mixture of a-aminopropionaldehyde diethylacetal 1 1.76 g.. 0.08 mole), p-fluorophenyl isothiocyanate (12.24 g.. 0.08 mole) in anhydrous benzene (80 ml.) was heated under reflux for /i hour. The solution was evaporated to dryness:

hydrochloric acid (6N, 80 ml.) was added and the mixture was heated under reflux for 17 hours. Product corresponding to l-(p-fluorophenyl)-4-methyl-Z-mercaptoimidazole (0.7 g., m.p. 212213) crystallized on cooling. The mother liquor was extracted with chloroform (3 X 75 ml.); the chloroform extract was evaporated to dryness and the residue was crystallized from ethylacetate (50 ml.) to give title compound (16.2 g.. m.p. 159161. dec.). A portion of this hydrochloride salt (9.0 g.) was dissolved in water, the solution was rendered basic to pH 9 with saturated sodium carbonate solution and extracted with chloroform to give oil (7.4 g.). This was redissolved in isopropanol (reagent grade, 10 ml.). ethanolic hydrochloric acid (9.9N, 3.5 ml.) was added, and title compound (6.4 g., m.p. 160162 dec.) crystallized. Recrystallization from isopropanol (10 ml.) gave screening sample (4.8 g., m.p. 159161ft 1 ec.).

Thin layer chromatography: 95 CHCl 5 3A EtOH for (TalcdzC5283j1 15.17, 1 10.27 S 1157 6161300 Found: C 53.06, H 5.34, N 10.28, S 11.90. Cl 13.01 Ultraviolet spectrum: 132 264 mu (6, 6.500)

EXAMPLE 44 1-(3-Pyridyl)-5-methyl-2-mercaptoimidazole by means of a vibromixer. After the addition was complete the reaction mixture was agitated at 3540 for 3 hours.

Salts were removed by filtration, the chloroform layer was separated and the aqueous layer was further extracted with chloroform (3 200 ml.). The chloroform extract was washed withwater, dried over sodium sulfate and evaporated to dryness. The residue was then distilled to yield title compound (2.4 g., m.p. 108109/9 mm.).

b. Desired Compound 1-Amino2.2-ethylene dioxypropane (1.17 g.. 0.01 mole) in isopropanol (4 ml.) was added dropwise to a cooled solution of 3-pyridine isothiocyanate in isopropanol (4 ml.).

The reaction mixture was heated under reflux for /2 hour and cooled. Ethanolic hydrochloric acid (9.9 N, 2.0 ml.) was added and the reaction mixture was again stirred under reflux for 1 hour. Product (2.2 g., m.p. 26927l. dec.)

crystallized on cooling. This hydrochloride salt was dissolved in water (10 ml.), the solution was rendered alkaline to pH 89 with saturated sodium carbonate solution and the precipitated solid was removed by filtration: yield (1.6 g., m.p. 227229). Recrystallization from isopropanol (50 ml.) gave screening sample (1.4 g., m.p. 225227). Anal. for C H N S (M.W. 191.25)

Calcd: C 56.51, H 4.75. N 21.96, S 16.77

Found: C 56.61. H 4.76, N 21.88, 5 16.80 Ultraviolet spectrum: M32" 256 my. (a, 12.500)

EXAM P LE 45 5-(3 ,4-Dichlorophenyl) l -methyl-2-mercaptoimidazole a. 3,4-Dichloro-a-isonitroacetophenone. Butyl nitrite 0.1 mole, 10.31 g.) was added dropwise over period of one hour to a solution of 3,4-dichloroacetophenone (0.1 mole. 18.9 g.) in anhydrous ether while anhydrous HCl was slowly bubbled through the solution at room temperature. HCI gas addition was continued for 15 minutes after addition of butyl nitrite was complete. Exothermic reaction suddenly occurred and the reaction mixture was stirred at room temperature for 6 /2 hours. The reaction mixture was evaporated to dryness under reduced pressure, the residue was suspended in benzene (50 ml.), the suspension was stored in refrigerator overnight and filtered; yield (10.8 g., m.p. l3. 943).

b. a-Amino-3,4-dichloroacetophenone Hydrochloride A suspension of 3,4-dich1oro-a-isonitrosoacetophenone (28.7 g., 0.13 mole) in a mixture of ethanol 28 (750 ml.) and concentrated hydrochloric acid (13.0 ml.) was hydrogenated at room temperature and atmospheric pressure in the presence of platinum on charcoal (5 percent. 3.0 g.). theoretical quantity of hydrogen was consumed in 15 minutes after which time hydrogen uptake ceased completely. The reaction mixture was filtered; the residue (crystallized product and catalyst) was dissolved in a mixture of boiling methanolwater and the hot solution filtered to remove catalyst. The combined ethanol, methanol and water solution was evaporated to dryness under reduced pressure at 50, the residue was crystallized from benzene to give the desired product (29.0 g., m.p. 2557).

c. 3,4-Dichlorophenyl-1-methyl-5.Z-mercaptoimidazole a-Amino-3 ,4-dichloroacetophenone hydrochloride (0.10 mole, 22.4 g.) was added to a solution of methyl isothiocyanate (0.1 mole, 7.13 g.) in anhydrous pyridine (150 ml.). The reaction mixture was stirred at for 18 hours. cooled and poured into ice water (ca. 600 ml.). Oily residue formed which crystallized on standing. This was collected. heated with 3N NaOH (500 ml): the hot solution was filtered hot to remove insoluble material, diluted with water (500 ml.). cooled and repeatedly washed with ether. The resulting solution was acidified with cone. HCl while cooling, the resulting solid was removed by filtration and washed with water; yield (12.7 g.. m.p. 18095). Recrystallization first from ethyl acetate (ca. 200 ml.. charcoal G-60), then from isopropanol (ca. 150 ml.) gave light tan product (8.1 g., m.p. 197 200 Two recrystallizations from benzene (spectro reagent grade, ml., charcoal G-60) gave the desired product (16.3 g., m.p. 197201).

Anal. for CmHgCizNZS l Ca1c'd.: C4634, H 3.11.N10.81,S12.37,C127.36 Found: C 46.62, H 3.14, N 10.98, S 12.33, ,Cl 27.07

EXAM PLE 46 1-Phenyl-5-(p-chlorophenyl)-2-mercaptoimidazolc a-Amino-p-chloroacetophenone hydrochloride (0.042 mole, 9.17 g.) was added to a cold solution of phenylisothiocyanate (0.042 mole, 5.67 g.) in pyridine (dry, 70 ml.). The mixture was stirred at room temperature for an hour and at 80 for hours. The solution was then poured into ice water (125 ml.) and the suspension was made basic with Na CO (satd. solution). The suspension was stirred for an hour at room temperature and the product was filtered off and washed well with water and then isopropanol. Beige crystals (11.13 g., m.p. 293-7) were obtained. The crude material was recrystallized from DMSO (125 ml.) and isopropanol (300 ml.) to give cream colored crystals (9.40 g., m.p. 3002). A second recrystallization from DMSO (95 ml.) and isopropanol (325 ml.) yielded 850 g. of the desired product: m.p. 3036.

M Anal. for C H ClN S Calcd.: C 62.83, H 3.86, N 9.77, S 11.18 Found: C 62.55, H 3.83, N 9.79, C 11.29

a. 1-(2-Pyridyl)-3-(p-chlorophenacyl)-2-thiourea a-Amino-p-chloroacetophenone hydrochloride (0.06 mole, 12.4 g.) was added to a cold solution of Z-pyridine isothiocyanate (0.06 mole, 8.25 g.) in dry pyridine (100 ml.). The mixture was stirred at room temperature for an hour and then at 80 for 15 hours. The mixture was poured into ice water (180 ml.) after cooling to room temperature and the solution was made basic with Na CO (satd. soln., 225 ml.). The crude product was filtered off and washed first with water and then isopropanol; Yield: 14.62 g., brown crystals, m.p. 207l0. Recrystallization from CHCI (400 ml.)- isopropanol (700 ml.) yielded colorless crystals (11.68 g., m.p. 2146 dec.). TLC-90 CHCl 10 32 Ethanol showed only major component.

b. 1-(2-Pyridyl)-5-(p-chlorophenyl)-2-mercaptoimidazole A solution of 1N HCI (0.0305 mole, 30.5 ml.) in methanol (abs. reag., 150 ml.) was added at room temperature to a suspension of 1(2-pyridyl)-3-(p-chlorophenacyl)-2-thiourea (0.0305 mole, 9,31 g.) in methanol (abs. reag., 200 ml.) and the mixture was heated under reflux for 3 hours; the solution became yellow immediately. The product precipitated out of the reaction mixture upon cooling. It was filtered off, washed with methanol, and dried in the vacuum oven; yield (6.33 g.. m.p. 2837). The crude product was recrystallized from methanol (abs. reag., 300 ml.) to yield pure product sample (4.63 g., m.p. 283 7). Ultraviolet spectrum: M512 300 my. Anal. for C H ClN S (M.W. 287.77)

Calcd: C 58.43, H 3.51, N 14.61, CI12.33, S 11.15

Found: C 58.14, H 3.77, N 14.53, Cl 12.41, S 11.14

As indicated above, the compounds described hereinabove can be employed as anti-inflammatory agents to treat the four cardinal symptoms of inflammation: swelling. 55

redness, pain and heat. The anti-inflammatory, analgesic and antipyretic effects in warm-blooded animals were determined by carrageenin, UV erythema. grid shock. hot box and antipyretic tests as follows:

1. a. Anti-inflammatory: Carrageenin Test Male rats, five per group, weighing between 150200 g., were given the test compounds orally 1 hour before carrageenin. 0.1 cc. of carrageenin was injected into the plantar area of the right hind paw. Three hours after administration .of carrageenin and 4 hours after administration of test compounds or vehicle, the rats were sacrificed. Right and left hind paws were removed and weighed. The difference between these paws was determined for all animals within a group and the average difference calculated. The average 70 difierence of the vehicle control group was used as a point of comparison for test groups. If the average difference for a test group was smaller than that of the vehicle control, protection is present and is expressed in percentage of vehicle control. The following illustrative results were obtained. 75 1-(3-Trifluoromethylphenyl)- TABLE 1 Dose Pro Z-Mercaptoimidazoles (mg/kg.) tection l-MethyI-5-t3-chlorophenyl)- I00 52 40 1,5-Dimethyl- I00 48 50 13 l-Ethyl-S-methyl- I00 29 l-n-ButyI-5methyl- I00 27 l-Allyl-S-methyl- 100 37 1-Cyclopropylmethyl-5-methyl- I00 43 l-Cyclohexyl-S-methyl- I00 54 l-(4-FIuorophenyl)-5-methyl- 100 49 1-(3-Fluorophenyl)-5-methyl- 100 37 1-(3-Tritluoromethylphenyl)-5-methyl- 100 34 lPhenyl- 100 37 I-(3,4-Dichlorophenyl)- I00 14 I-(4-Fluorophenyl- I00 41 l-MethyI-S-phenyl- 100 42 1-n-Propyl-5-methyl- I00 37 l-(4-FIuorophenyl)-4,5-dimethyl- I00 26 1-(2-Pyridyl)-5-methyl- I00 26 l-(3-Pyridyl)- 100 17 l-(3-Pyridyl)-5-methyl- 100 31 1-MethyLS-(4-fluorophenyl)- I00 53 50 39 l-n-Butyl-S-phenyl- I00 31 1-Methyl-5-t4-chlorophenyl)- I00 43 1-Methyl-5-(3-trifluoromethylphenyll- I00 43 5-(4-Chlorophenyh- 100 23 50 38 5-(3.4-Dichlorophenyl)-I-methyl- I00 58 S0 35 With l-butyl-5-methyl-2-(carboethoxymercapto)imidazole and 1-(4-fluorophenyl)-5-methyl-2-imidazole-mercaptoacetic acid the per c n t pr otection obtained at 100 mgJkg. is 21.

b. Anti-inflammatofyr lTtra violefEi'ythe ma T'est Guinea pigs. either sex. five per group. weighing between 275-375 grams. having their hair removed by using animal electrical clippers followed by chemical depilation with Nair. The next morning test compounds are given orally. Half of the total dose is given 1 hour before ultra violet irradiation. The other half is given immediately after U.V. exposure. Erythema is produced by 60 second exposure to ultra violet rays emitted by a Hanovia Analytical Model Quartz Lamp with a SOD-watt high-pressure mercury burner. In order to localize erythema to three 7 mm. areas. guinea pigs are confined in rubber gloves with three 7 mm. holes cut in them. Evaluation of results takes place 2 hours and 24 hours after ultra violet exposure. Erythema spots are scored from 0 to 3 giving a maximum total of 9 for an unprotected animal.

0 No visible signs of erythema l Faint trace of erythema '2 Definite but ill defined area of erythema 3 Definite and clearly defined area of erythema The scores of all animals within a given group are added together. A maximum score for any group of animals is 45 and is called the Maximum Degree of Inflammation. Any group with a degree of 'inflammation greater than vehicle 60 control has 0 percent protection. Groups with values less than the control groups have protection and this is expressed in percent. Table 11 shows illustrative results.

TABLE II Dose Pro- 2-Mercaptoimidazoles (mg/kg.) tection 1,5-Dimethyl- 100 50 42 25 $1 l-n-Butyl-S-methyl- 68 l-Allyl-S-methyl- 25 53 l'(4-Fluoropheny|) 50 40 l-mcthyLSphenyl- 100 78 l-Cyclohexyl-S-methyl- 50 28 1-(3-Fluorophenyl)-5-methyl- 100 55 TABLE II-Contjnued TABLE IV Dose Pro- Z-Mercaptoimidazoles (mg/kg.) tection Dose 7 2." r nlp (mg/kg.) tection 1-Cyclopropylmethyl-S-methyl- 50 40 l-(3-Trifluoromethylphenyl)- r 44 l,5-Dirnethyl- 80 32 py y r00 87 l-n-Butyl-S-methyl- 80 29 l-Phtmyl- 100 as 1-(4-Fluorophenyl)-5-methyl' 80 32 1-(4-Fluorophenyl)-4,5-dimethyl- 75 60 l-Ethyl-S-methyl- 80 l l-(Z-PyridyD-S-methyl- 100 61 40 37 l-Benzyl-S-methyl- 100 24 i8 l-(4Methoxyphenyl)- 100 31 lo l-(4-Fluorophenyl)- 80 2 l-(3-Pyridyl)- I00 36 l methyl-5-phenyl- 80 2 l-(2,4-Difluorophenyl)- 100 67 26 l-(3-Fluorophenyl)- 100 74 20 20 l-(2-Fluorophenyl)- 100 53 l-(3-Trifluoromethylphenyl)- 30 20 l-(4-Iodophenyl)- 100 48 12 l ,4-Dimethyl-5-phenyl- 100 57 l-Cyclopropylmethyl-S-methyl- 50 14 l-PhenyLS-methyl- 100 54 l-n-propyl-S-methyl- 80 2 l-Methyl-5-(4-methoxyphenyl)- 100 74 l-Phenyl- 30 I 5 50 71 1-(4-Fluorophenyl)-4,5-dimethyl- 23 25 42 40 I8 l-Methyl-5-(3-chlorophenyl)' r00 76 1-Methyl-5'(4-fluorophenyl) 100 83 ].(2 4.Diflu roph n 80 20 l,4Dirnethyl-5-(4-rnethoxyphenyl) 100 6| 20 l-(3-Fluorophenyll- 80 I 5 l,4Dimethyl-5-(4'fluorophenyl)- 100 36 |-(4-lodophenyl)- 26 l-Methyl-5-(4-chlorophenyD- 100 43 l-Merhyl-5-(3trifluoromethylphenyl)- 100 64 -w p y y r00 40 With l-(4-methoxyphenyl)-5-methyl-2-methylmercaptoimid- 5-(3,4- r hlo p eny y I00 60 azole, l-(4-fluorophenyl)-5-methyI-Z-(dimethylaminoethyl- 25 mercapto)-imidazole. l-(4-fluorophenyl)-5-methyI-Z-imida With l-(4-fluorophenyl)4-methyl-2-ethylmercaptoimidazole HCl the percent protection obtained at 100 mg./kg. is 2l.

2. a. Analgesic Activity: Grid Shock Test Five male Charles River mice, weighing 17-22 g. were used per group. Control readings were taken before oral administration and first test readings were taken 30 minutes after oral administration. Subsequent readings were taken at 30 minute intervals. Compounds to be administered orally were suspended in 3 percent corn starch solution. Concentrations varied but the maximum volume for p.o. administration was 0.44 cc. The mice were placed, individually, on a wire grid permitting freedom of movement. and exposed to a fairly constant and rapid increase in voltage. The point at which a mouse feels pain is determined on an oscilloscope by the distortion of a square wave caused by the mouse making and breaking contact on the grid. The average of two readings was taken at each time interval, on each mouse, and percent changes were calculated within each group. The following illustrative results zolemercapto acetic acid and l-(4-fluorophenyl)-4-methyl-2- ethylmercapto-imidazole HCl the percent protection obtained respectively, at 80. 50. 80 and mg./kg. is 24. I7. and 18.

3. Antipyretic Screen Male rats, 150 :5 g., were injected s.c. in the nape of the neck with IS percent suspension of Brewers Yeast Powder (Mead-Johnson) at rate of 1 cc./ I00 g. body weight. Sixteen to 18 hours later rectal temperatures were taken. Rats were rearranged to give four rats per group and to have relatively uniform temperatures. Test compounds were given orally in 2 percent gum acacia and one group received only the vehicle. One hour after the test material was given. rectal temperatures were again taken and continued at hourly intervals for 3 hours. The difference in temperature before drug administration and each hour after drug administration was calculated. The average of these temperature changes was used to compare test compounds with the vehicle control and standard (antipyrin). The following results were obtained.

were obtained. TABLE V TABLE III Avg. 50 Temp. Dose Peak Dose Change. Z-Mercaptoimidazoles (mg/kg.) Effect 2.M wi id (mg/kg.) "F.

1,5-Dimethyl- I00 40 lj-Dimgthyl- I00 3.9 y y 5 35 l-Ethyl-S-methylr00 3.2 l-n-Butyl5methyl- 250 I7 5 5 l-n-Butyl-S-methyl- I00 3.8 l-(4 Fluorophenyl)-5-methyl- 50 43 LAllyl-S-mgthyl- I00 5.9 l(4-FluorophenyD-S-methyl- 100 23 |-(4-Fluorophenyl)-5-methyl- I00 -6.7 l-methyLS-phenyl- 50 20 50 3.0 y 50 41 l-(4-Fluorophenyl)-5-methyl- 1 1-(4-FluorophenyD-S-phenyL 50 50 l-methyl-S-phenyl- I00 3.6 l-(4Fluorophenyl)- 50 I3 .Ph 100 -2.6 l-n-propyl-S-methyl- I00 5.3 l-Phenyl- 100 4. Toxicity Studies (48 Hour) Analgesic Activity; Hot Box Toxicities were determined on the basis of gross symptoms seen over a wide dose range of test compounds in CR mice. The vehicle was 3 percent corn starch. Five mice were used with each dose level. The route of administration was peroral. Results were as follows:

TABLE VI Z-Mercaptoimidazoles mgJkg.

l-Ethyl-S-methyl- I250 2/6 deaths l-(4-Fluorophenyl-4,5-dimethyl)- l250 2/6 deaths I M53: specifically, l-(4fluorophenyl)-2;mercaptoimidazole had the following Eons in various animals:

mouse 540 mgJkg. i.p. mouse 860 mg.lkg. p.o. rat ca: 700 mgJkg. p.o. rabbit over 500 mgJkg. p.o. dog over 300 mg./kg. p.o.

monkey (Saimiri) over 300 mg/kg. p.o.

The anti-inflammatory agents of this invention can be administered by any of the conventional means available for use in conjunction with pharmaceuticals. Pharmaceutical composition in dosage unit form comprise about mg. to about 500 mg. of the active ingredients.

To produce dosage units for peroral application, the active substances of general formula I or a salt thereof is combined, e.g. with solid powdered carriers such as lactose, sucrose, sorbitol, mannitol; starches such as potato starch, corn starch or amylopectin, also laminaria powder or citrus pulp powder; cellulose derivatives or gelatin, also lubricants such as magnesium or calcium stearate or polyethylene glycols (Carbowaxes) of suitable molecular weights may be added, to form compressed tablets or core tablets for sugar coating. The latter are coated, for example, with concentrated sugar solutions which e.g. can contain gum arabic, talcum and/or titanium dioxide, or they are coated with a lacquer dissolved in easily volatile organic solvents or mixture of organic solvents. Dyestufis can be added to these coatings, for example, to distinguish between difi'erent contents of active substance. Soft gelatin capsules (pearl-shaped closed capsules) and other capsules consist for example of a mixture of gelatin and glycerin and contain, e.g., mixtures of the active substance or a suitable salt thereof with Carbowax and hard gelatin capsules contain, for example, granulates of the active substance or a suitable salt thereof with solid, powdered cam'ers such as, e.g. lactose, sucrose, sorbitol, mannitol; starches such as potato starch, corn starch or amylopectin, cellulose derivatives or gelatin, as well as magnesium stearate or stearic acid. Suppositories are employed as dosage units for rectal application. These consist of a combination of the active substance or a suitable salt thereof with a neutral fatty base, or also gelatin rectal capsules can be employed which consist of a combination of the active substance of a suitable salt thereof with polyethylene glycols (Carbowaxes) of suitable molecular weight.

Ampoules for parenteral, particularly intramuscular administration preferably contain a water soluble salt of the best stability of the active ingredient is attained, e.g. by mixtures in suitable ratio of sodium suTrte, sodium bisulfite and/or ascorbic acid, or by the addition of other bufier substances such as citric acid and/or salts thereof. In addition, the ampoules can contain a slight amount of a usual 24 preservative.

Useful pharmaceutical formulations for administration of the compounds of this invention may be illustrated as follows:

Capsules Active Ingredient 10-500 mg. Lactose 20- [00 mg. Corn Starch, U.S.P. 20-l00 mg. Aerosolized Silica Gel 2-4 mg. Magnesium Stearate 1-2 mg.

Tablets Active Ingredient I00 mg. Microcrystalline Cellulose 50 mg. Corn Starch, U.S.P. mg. Lactose, U.S.P. 50 mg. Magnesium Stearate, U.S.P. 2 mg.

This tablet can also be sugar coated according to the usual art practices. Colors may be added to the coating.

According to the above disclosure. the invention thus pertains to anti-inflammatory active substituted 2-mercaptoimidazole derivatives of formula I. Encompassed in formula I are certain pyridyl substituted Z-mercaptoimidazole derivatives which seen by themselves as a separate aspect of this invention can be represented by the following formula RiN N wherein R, is 2-, 3- or 4-pyridyl R stands for hydrogen or lower alkyl and R represents lower alkyl or monocarbocyclic aryl. What is claimed is: l. A compound of the formula Rr-IL N wherein R is 2-, 3-, or 4-pyridyl R is hydrogen or lower alkyl and R is lower alkyl or phenyl or lower alkyl-, lower alkoxy-. fluoro-, bromo-, chloro-, iodoor triqb yts P sru t 2. A c5n-16ihd accor ng to claim 1 which is r-(i-r iid n 5-methyl-2-mercaptoimidazole.

3. A compound according to claim] which is l-(3-Pyridyl)- 5-methyI-Z-mercaptoimidazole.

4. A compound according to claim 1 which is l-(2-Pyridyl)- 5-(4-chlorophenyl)-2-mercaptoimidazole.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3, 622, 584 Dated November 23, 1971 Inventor(s) Karl J. Doebel and Andre R. Gagneux It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2 lines 24-25 "U .V. (MethanOD/I max: 223 My; 14000 A 2 max: 271 max: 273 my; 6 14000 I .R. (CHCl (7 c: 0) 1720 should read U.V. (ethanol and HCL) =1 max: 225 my; 5 17000;} 2 max: 273 1; E 14000;

I R. (CHCl 0 0: 0) 1720 Column 6, line 40 "oil (5 .4 g. b.p. 108 l12 t. f

should read oil (5.4 g., b.p. 108-112 (0.07 mm,

Column 15, line 34 "acid (cone. 6 .5 ml) should read acid (cone. 6 .4 ml) Signed and sealed this 25th day of July 1972.

(SEAL) Attest:

EDWARD I-'I.FLETGHER,JR. ROBERT GOT'I'SCHALK Attesting Officer Commissioner of Patents IJRM PC3-1050 (10-69l USCOMM-DC BO376-P69 LLS. GOVERNMENT PRINTING OFFICE I969 O3$S-JJ4 

2. A compound according to claim 1 which is 1-(2-Pyridyl)-5-methyl-2-mercaptoimidazole.
 3. A COMPOUND ACCORDING TO CLAIM - WHICH IS --(3-Pyridyl)-5-methyl-2-mercaptoimidazole.
 4. A compound according to claim 1 which is 1-(2-Pyridyl)-5-(4-chlorophenyl)-2-mercaptoimidazole. 